Summary

Using in situ hybridization, we have visualized cells in the rat central nervous system (CNS) that contain mRNA encoding the platelet-derived growth factor alpha receptor (PDGF-alpha R). After embryonic day 16 (E16), PDGF-alpha R mRNA appears to be expressed by a subset of glial cells, but not by neurons. The temporal and spatial distribution of PDGF-alpha R+ cells, together with 125I-PDGF binding studies on subsets of glial cells in vitro, suggests that PDGF-alpha R may be expressed predominantly, or exclusively, by cells of the oligodendrocyte-type-2 astrocyte (O-2A) lineage. This conclusion is supported by the fact that the numbers of PDGF-alpha R+ cells in developing and adult optic nerves correlate well with independent estimates of the number of O-2A progenitor cells in the nerve at equivalent ages. Small numbers of PDGF-alpha R+ cells are present in the brain at E16, at which time they are found outside the subventricular germinal zones, suggesting that these cells do not express PDGF-alpha R until after, or shortly before they start to migrate away from the subventricular layer towards their final destinations. Reduced numbers of PDGF-alpha R+ cells persist in the adult CNS. PDGF-alpha R is also expressed strongly in the meningeal membranes and choroid plexus, and in the inner limiting membrane of the retina.

Huntington's disease results in selective neurodegeneration in the forebrain and eventually death; there is currently no cure or therapy to slow its onset. Now, Ali Brivanlou and colleagues describe how isogenic stem cell lines with HTT repeat expansions give insights into the disease's cellular aetiology.

The resources pages of the Node and the BSDB have been combined and refurbished, with the new page designed to provide a range of useful links, including information on advocacy and outreach, new teaching resources for schools and databases for a wide range of species.